Anna Zordan is an agent with the British SIS.
Born in 1938, making her 27 at the start of the series, Anna Zordan was the daughter of an Hungarian diplomat and an American woman. Born in Budapest but educated in America and Switzerland, upon reaching her majority she chose to live in London, even as her parents seemed to be constantly on the go. Then on a surprise visit to their latest residence in Vienna, she discovered their bodies, both shot at close range by someone they apparently knew and trusted.
That is when the middle-aged man named Surratt showed up and helped her through the difficult time, seeing to the burial of her parents and the handling of their affairs. He left his card with her and told her to call if ever there was trouble as he also lived in London. She didn't expect to ever need him. She was wrong.
As the series opens, she is confronted with information about her parents' lives and is put into a deadly situation whose one resolution was killing a would-be attacker. Rembering Surratt, she calls and his help astonishes her.
Surratt was the head of a branch of British Intelligence, a man who had worked closely with her parents as they, too, were agents for the West. Seeing how well she had handled a dangerous situation, how relatively calm and undisturbed she was at having killed a man, and knowing her liberal attitude when it came to sex, he knew he had found a person o handle those special assignments when the normal male agent wouldn't do.
After considerable training in spycraft, Zordan was ready for duty.